What would you like to be added?

Add comprehensive internationalization (i18n) support to Gemini CLI to make it accessible to non-English speaking developers worldwide.

Proposed Implementation:

• Integrate react-i18next for translation management
• Support language detection via GEMINI_LANG environment variable
• Create translation framework for core UI components:
  • Help system (/help command output)
  • Error messages and dialogs
  • Shell confirmation prompts
  • Status indicators and feedback
• Maintain full backward compatibility (English as default)
• Enable community-contributed translations

Technical Approach:

• Minimal performance impact through lazy loading of translation resources
• Type-safe translation keys using TypeScript
• Fallback mechanism to English for missing translations
• Integration with existing React + Ink architecture

Proposed Languages (Initial):

• English (default, no changes needed)
• Chinese (Simplified) - Large developer community
• Spanish - Second most spoken language globally
• French - Strong developer community in Europe/Africa

Example Implementation:

// Before
<Text>Basics:</Text>

// After
<Text>{t('help.basics')}</Text>

Why is this needed?

1. Global Accessibility: Gemini CLI is used by developers worldwide, but currently all UI text is hardcoded in English, creating barriers for non-English speakers.

2. Large International User Base: Search of existing issues reveals numerous IME-related problems for CJK languages (The UI is strange when using Japanese input. #4481, Poor real-time display of Korean IME composition in Gemini CLI #3014, Bug: Chinese IME composition is not handled correctly in the CLI #5833, Korean (Hangul) input drops the last character in Gemini CLI #2797, Chinese input BUG on MacOS #2618, etc.), indicating significant international usage. These users would greatly benefit from localized UI text.

3. Inclusive Design: Aligns with Google's commitment to inclusive design and global accessibility standards.

4. Community Growth: Enables broader community adoption and contribution from international developers.

5. Industry Standard: Modern CLI tools (like git, docker, npm) increasingly support internationalization.

6. Complementary to Existing Work: This proposal would complement the ongoing IME fixes by providing localized interface text for the same international users experiencing input issues.

Additional context

Research Findings:

• Analyzed the current codebase and identified ~197 user-facing text strings that would benefit from internationalization
• Searched existing issues - no duplicate requests found for UI language localization
• Current hardcoded text examples: "Basics:", "Shell mode", "Add context", error messages, confirmation dialogs

Technical Feasibility:

• Implementation can be done incrementally without breaking existing functionality
• React + Ink architecture already supports i18n libraries
• Estimated implementation: 2-3 weeks for core framework + initial languages

Impact Assessment:

• Zero breaking changes to existing functionality
• Opt-in feature (English remains default)
• Enables community contribution of additional languages
• Improves accessibility for international developers

Implementation Plan:

1. Set up i18n infrastructure with react-i18next
2. Extract hardcoded strings to translation keys
3. Implement language detection via environment variables
4. Add initial language packs (Chinese, Spanish, French)
5. Create contribution guidelines for community translations

I have signed the Google CLA and am prepared to implement this feature following the project's contribution guidelines.